FreeBSD laptop with: 56k modem, ethernet, Xfree86

Gary Corcoran garycor at
Tue Jun 10 23:13:04 PDT 2003

Andy Sparrow wrote:
> Ironically enough, although they no longer ship a Lucent modem, IBM used
> to,
> and the ltmdm  port works fine[0].

> [0] This superb piece of work is actually a loader that loads a software
> image into the modem and then "talks" to it for you, if I understand
> correctly - it's more like a "softmodem" than a "winmodem". CPU load is
> not noticably increased at all with a PIII-600.

You have your terminology backwards.  A "softmodem" is when the realtime
DSP functions are performed on your CPU, taking a good chunk of it.
The "ltmodems" are so-called "winmodems", where the CPU just takes the
place of the "controller", which handles things like interpreting the
"AT" commands, and was typically something like a little Z-80 microprocessor
(remember those? :) on-chip.  So you can see that it takes next-to-nothing
of a modern Pentium CPU to handle that, which is why you don't notice any
increase in load with a "ltmodem"...


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